Thin film magnetic tape head and method of manufacturing therefor

ABSTRACT

A magnetic tape head assembly is provided along with a method of manufacturing a magnetic tape head. The magnetic tape head comprises a cluster of thin film inductive or magnetoresistive read/write elements, an I-block preferably made of a ceramic material, a U-bar also preferably made of a ceramic material, and a base preferably made of a ceramic or metal material. The U-bar has a substantially U-shaped form providing a recess into which the I-block and the cluster are fixed. A bottom surface of the U-bar, I-block, and cluster is fixed to the base to form a slider assembly. A top surface of the U-bar, I-block, and cluster is machined or etched to form one or more tape bearing surfaces thereon.

FIELD OF THE INVENTION

[0001] The invention relates to a thin-film magnetic head for use inmagnetic tape recording. Further, the invention relates to a method ofproducing such a thin-film magnetic tape head.

DESCRIPTION OF THE RELATED ART

[0002] Ever growing demands for high performance and low cost magneticrecording for application in tape backup systems urge the need forimproved product design and related manufacturing processes.

[0003] For the special features of linear longitudinal tape head design,conventional head structures heretofore typically consist of four tofive separate components to form a slider on which a tape bearingsurface is built. These components are glued together with highperformance adhesive to form a rigid, non-moving body to service thehigh-speed, high-pressure and highly abrasive tape contact for its readand write function.

[0004] The multitude of components in the prior art designs increasesthe complexity in the assembly processes. The stability of a headstructure built with many building blocks also lowers the stability ofthe combination structure.

[0005] For proper operation, different pieces of the tape bearingsurface must be highly coplanar in order to ensure sufficient tapecontact. Any minute shift of one component relative to the others canproduce a tiny step on the tape bearing surface, which may result in anincrease in the effective separation distance between the tape and head.In the latter case, the read/write signal is attenuated.

[0006] Conventional head structures have the common problem of too manycomponents and involve a relatively large amount of adhesive bonding toform the structure. The multitude of components adhered together canrender the magnetic head structurally unstable. During service life,individual portions of the combination head can shift relative to eachother due to aging of the adhesive and other stresses, formingdetrimental stepped tape bearing surfaces.

BRIEF SUMMARY OF THE INVENTION

[0007] An object of the present invention is to overcome these and othershortcomings of structural instability in the prior art designs.

[0008] Another object of the present invention is to provide astructurally sound magnetic recording head with simplified manufacturingprocesses and material control.

[0009] In accordance with the present invention, a magnetic taperecording head is provided which includes a U-bar, which is a U-shapedframe having a back portion extending in a longitudinal direction andtwo spaced-apart leg portions extending from the back portion of theframe in a lateral direction. The magnetic tape head also includes aceramic block, called an I-block, which is fixed to the frame such thatthe I-block partially fills the space between the leg portions of theframe. The magnetic tape head further includes a cluster fixed to theframe such that at least a portion of the cluster partially fills thespace between the leg portions of the frame. In addition, the I-blockand the cluster are arranged such that the I-block is interposed betweenthe cluster and the back portion of the frame.

[0010] One or more ridges are formed in a top surface of the combinationof the U-bar, the I-block, and the cluster. This top surface is parallelto a plane defined by the longitudinal direction in which the backportion of the U-bar extends and by the lateral direction in which theleg portions of the U-bar extend. Each of these ridges provides a tapebearing surface of the magnetic tape head. One of these tape bearingsurfaces may include a portion of the cluster for interfacing with atape, and for improved structural stability this tape bearing surfacemay also include a portion of the I-block.

[0011] The combination of the U-bar, the I-block, and the cluster may befixed to a base member preferably made of ceramic or metal, such asaluminum, to further improve structural stability.

[0012] According to another aspect of the present invention, a method ofmanufacturing a magnetic tape head is provided including a step ofproviding a U-bar, which is a U-shaped frame having a back portionextending in a longitudinal direction and two spaced-apart leg portionsextending from the back portion of the frame in a lateral direction. Themethod also includes a step of fixing a ceramic block, called anI-block, to the frame such that the I-block partially fills the spacebetween the leg portions of the frame. The method further includes astep of fixing a cluster to the frame such that at least a portion ofthe cluster partially fills the space between the leg portions of theframe. In addition, the I-block and the cluster are arranged such thatthe I-block is interposed between the cluster and the back portion ofthe frame. Finally, the method includes a step of forming at least oneridge in a surface which includes a portion of the top surface of theU-bar as described above.

[0013] According to still another aspect of the present invention, amethod of manufacturing a magnetic tape head is provided including astep of providing a frame bar having a back portion extending in alongitudinal direction and a plurality of spaced-apart leg portionsextending from the back portion of the frame bar in a lateral direction.The method also includes a step of fixing at least one ceramic block,called an I-block, to the frame bar such that the I-block partiallyfills a space between two respective ones of the plurality of legportions of the frame bar. The method further includes a step of fixinga cluster to the frame bar such that at least a portion of the clusterpartially fills the space between two respective ones of the pluralityof leg portions of the frame bar. In addition, the I-block and thecluster are arranged such that the I-block is interposed between thecluster and the back portion of the frame bar. In accordance with thismethod, one or more magnetic tape heads may be assembled from a singleframe bar. This may be accomplished by including a step of cutting theframe bar into at least two pieces, at least one of the two piecesincluding a portion of the frame bar, the at least one I-block, and theat least one cluster. Also, this method includes a step of forming atleast one ridge in a surface which includes a portion of the top surfaceof the frame bar as described above. The step of forming at least oneridge may be performed before the step of cutting the frame bar tofacilitate forming ridges in one or more magnetic tape heads at once.

[0014] Finally, the above methods may include a step of fixing thecombination of the U-bar, the I-block, and the cluster to a base memberpreferably made of ceramic or metal, such as aluminum, to furtherimprove structural stability. Also, one or more of the steps ofproviding an I-block bar, which is an uncut plurality of I-blocks, andproviding a cluster bar, which is an uncut plurality of clusters,cutting the I-block bar into at least two pieces, and cutting thecluster bar into at least two pieces. In addition, a step of fixing theI-block bar to the cluster bar may be performed before the steps ofcutting the I-block bar and cutting the cluster bar, so that the I-blockbar and the cluster bar are cut in a single operation.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0015] Other advantages and features of the invention will become moreapparent with reference to the following detailed description of theinvention in connection with the accompanying drawings, wherein likereference numerals have been applied to like elements, in which:

[0016]FIG. 1 is a perspective exploded view of a magnetic tape head inaccordance with the present invention;

[0017]FIG. 2 is a perspective view showing an intermediate step ofmanufacturing a magnetic tape head in accordance with the presentinvention;

[0018]FIG. 3 is a perspective view of a magnetic tape head in accordancewith a first embodiment of the present invention;

[0019]FIG. 4 is a perspective view of a magnetic tape head in accordancewith a second embodiment of the present invention;

[0020]FIG. 5A is a perspective view of a frame bar structure used in amethod of manufacturing a magnetic tape head in accordance with thepresent invention;

[0021]FIG. 5B is a perspective view of an I-block bar and a cluster bar,both used in a method of manufacturing a magnetic tape head inaccordance with the present invention;

[0022]FIG. 6 is a perspective view of a step of a method ofmanufacturing a magnetic tape head in accordance with the presentinvention;

[0023]FIG. 7 is a perspective view of a step of a method ofmanufacturing a magnetic tape head in accordance with the presentinvention;

[0024]FIG. 8 is a perspective view of a step of a method ofmanufacturing a magnetic tape head in accordance with the presentinvention; and

[0025]FIG. 9 is a perspective view of a step of a method ofmanufacturing a magnetic tape head in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

[0026] Referring to FIG. 1, a first preferred embodiment of the presentinvention is shown. A slider 50 of the present invention includes acluster 10 comprising a plurality of inductive thin-film ormagnetoresistive read/write transducer elements (not shown). Alsoincluded are an I-block 20 and a U-bar 30, both of which are preferablymade of a ceramic material, such as aluminum oxide titanium carbide(AlTiC) or ferrites. The combination of the cluster 10, the I-block 20,and the U-bar 30 are fixed to a base plate 40. Each of the cluster 10,the I-block 20, and the U-bar 30 may be fixed at their respectivepositions using a structural adhesive, such as Bondline ₆₄₆₀™ fromBondline Electronic Adhesive, Inc. or Ablebond 931™ from AblestikElectronic Materials & Adhesives. The surface A is a receiving surfacefor the I-block 20, the significance of which will be revealed below.

[0027] The cluster 10 of the present invention may be a cluster or chipread/write head such as an inductive thin-film head or magnetoresistivehead, comprising a plurality of transducer elements for reading/writingdata to a recording medium such as a recording tape. The cluster 10 ispreferably cut to high dimensional and geometrical precision to ensurecontrolled bond lines 60, 70, and 80 shown in FIG. 2 after assembly.

[0028] The I-block 20 serves to protect the delicate transducer devicesof the cluster 10 so that the transducer devices will not be damagedduring manufacturing. The I-block 20 also serves to simplify themanufacturing process, as will be discussed below.

[0029] The U-bar 30 forms a frame onto which the I-block 20 and thecluster 10 are fixed. As shown in FIG. 1, the U-bar 30 has asubstantially U-shaped form, which includes a back portion extending ina longitudinal direction and two leg portions extending in a lateraldirection from the back portion. The U-shape of the U-bar 30 provides aspace for positioning the I-block 20 and the cluster 10, so that theU-bar 30 partially frames the combination of the I-block 20 and thecluster 10. The surfaces of the U-bar 30 facing this space arepreferably provided with precise dimensional and geometric accuracy sothat the cluster 10 and the I-block 20 fit into the space leaving only asmall glue line of adhesive. A thickness of a preferred glue line ateach of the bond lines 60, 70, 80, and 90 is in the range of0.0001-0.0005 inches, depending on the requirements of the adhesive usedto join the cluster 10 and the U-bar 30

[0030]FIG. 2 shows how the I-block 20 and the cluster 10 are positionedand partially framed by the U-bar 30. The combination of the cluster 10,the I-block 20, and the U-bar 30 are bonded to the base plate 40 to formthe basic structure of the slider 50.

[0031]FIG. 3 shows a final magnetic head assembly 120 in accordance withthe first embodiment of the present invention. This final assembly 120includes tape bearing surfaces 100 and 110, which are narrow ridgesformed by machining or etching adjacent portions of a top portion of theslider 50. Once formed, it is preferable to profile and highly-polishthe tape bearing surfaces 100 and 110 to allow for a smooth, lowfriction contact for a magnetic tape to pass over.

[0032] As mentioned above, the I-block 20 serves to simplify themanufacturing of the magnetic recording head of the present invention.It is preferable to have a controlled bond lines surrounding the cluster10. However, it is difficult to achieve a desired level of precision onthe surface A (shown in FIG. 1) of the U-bar 30 in order to adequatelyachieve the controlled bond line at the device surface of the cluster10. However, by interposing the I-block 20 between the cluster 10 andthe surface A, the I-block 20 can compliment a geometrical mismatchbetween the cluster 10 and the surface A of the U-bar 30. The bond line70 between the I-block 20 and the cluster 10 may be controlled withrelative ease, so that the bond line 90 between the I-block 20 and theU-bar 30 becomes less critical, thereby reducing the precision requiredfor creating the surface A of the U-bar 30.

[0033] In the first embodiment, two tape bearing surfaces are provided.Of the two, only the first tape bearing surface 110 includes a portionof the read/write transducers of the cluster 10. The major function ofthe second tape bearing surface 100 is to stabilize a magnetic tape asthe magnetic tape is passing over the tape head. This type of inactive,stabilizing rail (the second tape bearing surface 100) is generallyreferred to as an outrigger.

[0034]FIG. 4 shows a magnetic head assembly 160 in accordance with asecond embodiment of the present invention. The magnetic head assembly160 of the second embodiment is formed from the slider 50 as shown inFIG. 2, including a cluster 10, an I-block 20, a U-bar 30, and a base 40as described above for the first embodiment. However, as shown in FIG.4, the magnetic head assembly 160 of the second embodiment has only onetape bearing surface 150 as opposed to two tape bearing surfaces in thefirst embodiment. Thus, the second embodiment provides the option of notproviding an outrigger.

[0035] FIGS. 5-9 show the present invention as produced by analternative method of manufacturing. In summary, this method involvesthe bonding, machining, and lapping of a plurality of heads in a singleframe bar, thus reducing manufacturing costs.

[0036]FIG. 5A shows a frame bar 200 in which three recesses areprovided. The frame bar 200 is essentially a row of uncut U-bars, and ispreferably made of a ceramic material. FIG. 5B shows a cluster bar 10′and an I-block bar 20′. The cluster bar 10′ is essentially a row ofuncut clusters 10, and the I-block bar 20′ is essentially a row of uncutI-blocks 20.

[0037] As shown in FIG. 6, a plurality of I-blocks 20 and a clusters 10are cut from the I-block bar 20′ and the cluster bar 10′, respectively.Preferably, the cluster bar 10′ and the I-block bar 20′ are fixed to oneanother before being cut into individual cluster 10/I-block 20assemblies. Each cluster 10/I-block 20 assembly is fixed into arespective recess of the frame bar 200, such that each I-block 20 isfixed between each respective surface A and a respective cluster 10. Abase bar 210 is provided, and bottom surface of the combination of theframe bar 200, I-blocks 20, and clusters 10 is bonded to the top surfaceof a base bar 210 to form a slider bar 220 as shown in FIG. 7. Again,each of these items may be fixed to one another using a structuraladhesive such as the examples provided above.

[0038] Once the slider bar 220 has been assembled, narrow rails areformed in a top surface of the slider bar 220 to provide two tapebearing surfaces 230 and 240 as shown in FIG. 8. Then, individual headsare cut off from the slider bar 220 to form a final magnetic headassembly 120 as shown in FIG. 9.

[0039] While this method is illustrated in FIGS. 5-9 by way of anexample in which three magnetic heads are assembled at once, one skilledin the art would appreciate that this method is not restricted to three,but may be adapted to manufacture any number of magnetic heads at once.In addition, this method may be easily adapted to assemble heads inaccordance with the second embodiment, wherein only a single tapebearing surface is formed. Finally, the descriptions above are notintended to restrict in any way the order in which the frame bar 200,each I-block 20, each cluster 10, and the base bar 210 must beassembled.

[0040] The above-described method may also be modified such thatportions of the slider bar 220 are cut off before forming tape bearingsurfaces thereon. Such a modification may be desirable, for example, ifmagnetic heads having differing numbers of tape bearing surfaces aredesired.

[0041] Although the present invention has been fully described by way ofpreferred embodiments and methods, one skilled in the art willappreciate that other embodiments and methods are possible withoutdeparting from the spirit and scope of the present invention. Forexample, while embodiments have been provided with one or two tapebearing surfaces, it may be desirable to provide any number of tapebearing surfaces

What is claimed is:
 1. A tape head assembly comprising: a frame having agenerally U-shaped form, having a back portion extending in alongitudinal direction and two spaced-apart leg portions extending fromthe back portion in a substantially lateral direction; a block fixed tothe frame such that the block partially fills a space between the legportions; and a cluster fixed to the frame and the block such that atleast a portion of the cluster partially fills the space between the legportions and such that the block is interposed between the cluster andthe back portion of the frame, said frame having a first surface havingat least one ridge formed therein extending in the longitudinaldirection.
 2. A tape head assembly in accordance with claim 1, whereinthe at least one ridge has a tape bearing surface.
 3. A tape headassembly in accordance with claim 2, wherein the at least one ridgeincludes a portion of the cluster.
 4. A tape head assembly in accordancewith claim 3, wherein the at least one ridge further includes a portionof the block.
 5. A tape head assembly in accordance with claim 4,wherein the first surface has a plurality of ridges.
 6. A tape headassembly in accordance with claim 1, wherein the frame has a secondsurface opposite the first surface and wherein the tape head assemblyfurther comprises a base member fixed to the second surface of theframe.
 7. A tape head assembly in accordance with claim 1, wherein thecluster includes at least one thin-film transducer element.
 8. A methodof manufacturing a tape head assembly comprising the steps of: providinga frame having a generally U-shaped form, the frame having a backportion extending in a longitudinal direction and two spaced-apart legportions extending from the back portion in a substantially lateraldirection; fixing a block to the frame, the block partially filling thespace between the leg portions; fixing a cluster to the frame, thecluster partially filling the space between the leg portions, such thatthe block is interposed between the cluster and the back portion of theframe; and forming at least one longitudinal ridge which includes aportion of the first surface of the frame.
 9. A method of manufacturinga tape head assembly in accordance with claim 8, wherein the step offorming the at least one longitudinal ridge includes forming a tapebearing surface on the at least one longitudinal ridge.
 10. A method ofmanufacturing a tape head assembly in accordance with claim 9, whereinthe at least one longitudinal ridge includes a portion of the clusterassembly.
 11. A method of manufacturing a tape head assembly inaccordance with claim 10, wherein the at least one longitudinal ridgeincludes a portion of the block.
 12. A method of manufacturing a tapehead assembly in accordance with claim 11, wherein the step of formingthe at least one ridge includes forming a plurality of ridges.
 13. Amethod of manufacturing a tape head assembly in accordance with claim 8,further comprising the step of fixing a base member to the secondsurface of the frame, said second surface being opposite to said firstsurface.
 14. A method of manufacturing a tape head assembly inaccordance with claim 8, further comprising the steps of: providing ablock bar; fixing a cluster bar to the block bar; and cutting the thusfixed block bar and cluster bar into at least two portions, wherein oneof the at least two portions includes the block and the cluster.
 15. Amethod of manufacturing a tape head assembly comprising the steps of:providing a frame bar having a back portion extending in a longitudinaldirection and a plurality of spaced-apart leg portions each extending ina substantially lateral direction; fixing at least one block to theframe bar, the block partially filling a space between two respectiveones of the plurality of leg portions; fixing at least one cluster tothe frame bar, the cluster partially filling the space between the tworespective ones of the plurality of leg portions, such that the at leastone block is interposed between the at least one cluster and the backportion of the frame bar; and forming at least one longitudinal ridgewhich includes a portion of the first surface of the frame bar.
 16. Amethod of manufacturing a tape head assembly in accordance with claim15, further comprising the step of cutting the frame bar into at leasttwo pieces, wherein the step of cutting the frame bar is performed afterthe steps of fixing the at least one block and fixing the at least onecluster, wherein one of the at least two pieces includes the at leastone block and the at least one cluster.
 17. A method of manufacturing atape head assembly in accordance with claim 16, wherein the step offorming the at least one ridge is performed before the step of cuttingthe frame bar.
 18. A method of manufacturing a tape head assembly inaccordance with claim 17, wherein the step of forming the at least onelongitudinal ridge includes forming a tape bearing surface on the atleast one longitudinal ridge.
 19. A method of manufacturing a tape headassembly in accordance with claim 18, wherein the at least one ridgeincludes a portion of the at least one cluster.
 20. A method ofmanufacturing a tape head assembly in accordance with claim 19, whereinthe at least one ridge includes a portion of the at least one block. 21.A method of manufacturing a tape head assembly in accordance with claim20, wherein the step of forming the at least one ridge includes forminga plurality of ridges.
 22. A method of manufacturing a tape headassembly in accordance with claim 15, further comprising the step offixing a base bar to a second surface of the frame bar, said secondsurface being opposite to said first surface.
 23. A method ofmanufacturing a tape head assembly in accordance with claim 22, furthercomprising the step of cutting the frame bar into at least two pieces,wherein the step of cutting the frame bar is performed after the stepsof fixing the at least one block and fixing the at least one cluster,wherein one of the at least two pieces includes the at least one block,the at least one cluster, and a portion of the base bar.
 24. A method ofmanufacturing a tape head assembly in accordance with claim 23, whereinthe step of forming the at least one ridge is performed before the stepof cutting the frame bar.
 25. A method of manufacturing a tape headassembly in accordance with claim 15, further comprising the steps of:providing a block bar; fixing a cluster bar to the block bar; cuttingthe thus fixed block bar and cluster bar into at least two portions,wherein one of the at least two portions includes the at least one blockand the at least one cluster.